Ebro River - Clickable Map of the Roman Empire - First Century AD

Ebro River
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The Ebro River Major river in northeast Spain flowing south of the Pyrenees mountains. The Ebro river became a dividing line after the First Punic War.

Ebro River The Ebro (Spanish, pronounced [ˈeβɾo]) or Ebre (Catalan, pronounced [ˈeβɾə] or [eβɾe]) is Spain's most voluminous river. Its source is in Fontibre (Cantabria). It flows through cities such as Miranda de Ebro (Castile and Leon), Logro�o (La Rioja), Zaragoza (Aragon), and the Catalan cities of Flix, Tortosa, and Amposta before discharging in a delta on the Mediterranean Sea in the province of Tarragona.

Name
The Romans named this river Iber (Iberus Flumen), hence its current name (but probably derives from the Greek H�vros, Ἑβρος). Arguably the whole peninsula and some of the peoples living there were named after the river.

History
In antiquity, the Ebro was used as the dividing line between Roman (north) and Carthaginian (south) expansions after the First Punic War. When Rome, fearful of Hannibal's growing influence in the Iberian Peninsula, made the city of Saguntum (considerably south of the Ebro) a protectorate of Rome, Hannibal viewed this treaty as an aggressive action by Rome and used the event as the catalyst to the Second Punic War.

One of the earliest Cistercian monasteries in Spain, Real Monasterio de Nuestra Se�ora de Rueda (Royal Monastery of Our Lady of the Wheel), is located on the banks of the Ebro in Aragon. This edifice survives to the present intact, having been established in the year AD 1202. The monastery is strongly connected to the Ebro, since it used one of the first large waterwheels established in Spain for the production of power. The monastery also diverted flow from the Ebro to create a circulating hydrological central heating system for its buildings.

The river Ebro was the initial starting ground of one of the most famous Republican offensives during the Spanish Civil War, in 1938. The offensive itself, known as the Battle of the Ebro, ended in defeat for the Republican forces, even though they enjoyed initial success in its first stages. However, they were not able to reach the desired objective of Gandesa.

Delta geography
The Ebro Delta (in Catalan: Delta de l'Ebre), in the Province of Tarragona, Catalonia, is one of the largest wetland areas (320 km�) in the western Mediterranean region. The Ebro delta has grown rapidly�the historical rate of growth of the delta is demonstrated by the town of Amposta. This town was a seaport in the 4th Century, and is now located well inland from the current Ebro river mouth. The rounded form of the delta attests to the balance between sediment deposition by the Ebro and removal of this material by wave erosion.

The modern delta is in intensive agricultural use for rice, fruit (in particular citrus), and vegetables. The Ebro delta also hosts numerous beaches, marshes, and salt pans that provide habitat for over 300 species of birds. A large part of the delta was designated as Ebro Delta Natural Park in 1983 (Parc Natural del Delta de l'Ebre).[2] A network of canals and irrigation ditches constructed by both agricultural and conservation groups are helping to maintain the ecologic and economic resources of the Ebro Delta.

Flow and floods
The Ebro river is the most important river in Spain, 928 km in length and with a drainage basin of 85,550 km�. However, the mean annual flow decreased by approximately 29% during the 20th Century due to many causes: the construction of dams, the increasing demands for irrigation and the evaporation (higher than the rainfall, due to low rainfall, high sunshine and strong and dry winds) from reservoirs in the river basins. This situation has a direct impact on the deltaic system at the mouth of the river because its hydrological dynamics are mainly controlled by the river discharge, and the introduction of the salt wedge is favoured by the low tidal range (20 cm) and the diminution on the river discharge. The mean annual river flow is approximately the critical flow which determines the formation and the break-up of the salt wedge. Thus, when the river discharge is between 300 and 400 m�, the salt wedge can occupy the last 5 km of the estuary, but when the discharge is between 100 and 300 m�, the salt wedge can advance up to 18 km from the mouth. For less than 100 m�, the salt wedge quickly advances to its maximum extent, reaching 32 km from the mouth. In addition to decreased mean annual flow, the increased river regulation in the Ebro basin has produced daily and seasonal changes in the flow pattern.

With regards to the sediment load, several authors conclude that the sediment load was reduced by more than 99% during the last century. The drastic reduction in sediment transport implies a sediment deficit in the Delta, which is causing the erosion of the coastline. This erosion together with the sinking of the Delta produced by soil compaction and tectonic subsidence cannot be balanced by the deposition of fluvial sediments, nearly all of them retained in the dams. - Wikipedia